Novak Djokovic defeated France's Ugo Humbert 4-6, 6-3, 6-4 in his opening match at the Basel tournament on Wednesday.
The victory keeps the 39-year-old player's bid for a record 19th qualification to the season-ending ATP Finals on course.
Djokovic will face Germany's Jan-Lennard Struff in the next round, against whom he holds an 8-0 career record.